Time difference function:
timestampdiff
语法：timestampdiff(interval, datetime1,datetime2)
Results: Returns the time difference (time period 2- 1), the results given by the unit interval parameter.
- frac_second ms (low version is not supported by second, and then divided by 1000)
- second seconds
- minute minute
- hour hour
- day of days
- week week
- month month
- quarter quarter
- year in
Note: MySQL only supports recording and computing milliseconds after 5.6, if a previous version, preferably in a database other than datetime field types, then create a field for storing int milliseconds, and then converted his own calculations.
# All formats the SELECT TIMESTAMPDIFF (FRAC_SECOND, ' 2012-10-01 ' , ' 2013-01-13 ' ); # does not support the SELECT TIMESTAMPDIFF (SECOND,, ' 2012-10-01 ' , ' 2013-01-13 ' ) ; # 8.9856 million the SELECT TIMESTAMPDIFF (MINUTE, ' 2012-10-01 ' , ' 2013-01-13 ' ); # 149760 the SELECT TIMESTAMPDIFF (HOUR, ' 2012-10-01 ' , ' 2013-01-13 ' );# 2496 SELECT TIMESTAMPDIFF(DAY,'2012-10-01','2013-01-13'); # 104 SELECT TIMESTAMPDIFF(WEEK,'2012-10-01','2013-01-13'); # 14 SELECT TIMESTAMPDIFF(MONTH,'2012-10-01','2013-01-13'); # 3 SELECT TIMESTAMPDIFF(QUARTER,'2012-10-01','2013-01-13'); # 1 SELECT TIMESTAMPDIFF(YEAR,'2012-10-01','2013-01-13'); # 0
datediff
Syntax: pass two date parameters, compare DAY days, minus the first parameter of the second parameter values day
SELECT DATEDIFF('2013-01-13','2012-10-01');# 104
timediff
Syntax: timeDiff (TIME1, TIME2)
Results: Returns two time difference obtained by subtracting, time1-time2
SELECT TIMEDIFF('2018-05-21 14:51:43','2018-05-19 12:54:43');# 49:57:00
Other date functions
- now () function returns the date when the current time every minute
- curdate () function returns the date information
- curtime () function returns the current time information of minutes and seconds
- When a date to the date contained Minutes formatted date date, use DATE (time) function
# Other date functions the SELECT the NOW (); # 2018 - 05 - 21 is 14 : 41 is : 00 the SELECT CURDATE (); # 2018 - 05 - 21 is the SELECT CURTIME (); # 14 : 41 is : 38 is the SELECT DATE (the NOW ()); # 2018 - 05 - 21 is the SELECT SYSDATE (); # 2018 - 05 - 21 is 14 : 47 : . 11 the SELECT CURRENT_TIME (); # 14:51:30 SELECT CURRENT_TIMESTAMP; # 2018-05-21 14:51:37 SELECT CURRENT_TIMESTAMP(); # 2018-05-21 14:51:43
Note: now () and sysdate () is similar, except now () will get the start in the implementation, but sysdate () can be obtained dynamically when the function execution.